1. Field of the Invention
This invention relates to an apparatus for detecting the concentration of a solution by visual means.
2. Description of the Prior Art
In the past various apparatus for detecting the concentration of solutions by surface tension methods have been utilized. In U.S. Pat. No. 3,483,737 to Jennings, Jr. et al, entitled "Apparatus for Measuring Interfacial Tension," there is disclosed a rotary wheel having openings therein across which films can form. In U.S. Pat. No. 2,473,553 to Stokes, entitled "Method of and Apparatus for Measuring the Film Strength of Liquids," there is disclosed photoelectric means for measuring the concentration of a liquid.